Analysis of cellular telephone networks, e.g. those using the Global System for Mobile communications (GSM) standard, is used to predict the load on a network and how much load it can carry without causing difficulties. In particular, such analysis can be used to determine what network resources are required to provide an acceptable level of performance to users of the network, a process referred to as network dimensioning. For example, the analysis can determine blocking rates, which represent the likelihood that a request to establish an additional call is denied or ‘blocked’ to prevent established calls or other network services from suffering performance degradation.
Network dimensioning includes estimating resource quantities, such as the number of base transceiver stations, needed to support a certain network traffic load. Network dimensioning can be used to design a first generation deployment of a new network, referred to as a ‘green-field’ network, or to determine to what extent an existing network is or will be under- or over-loaded (for planning future capacity requirements).
The outcome of the network dimensioning process is used in radio network design processes to provide an early indication of network size and cost. The dimensioning phase is later followed by a planning phase during which more specific information is collected, enabling a more detailed analysis. Alternatively, the dimensioning process can be used to assess whether sufficient network capacity is installed for a current, or projected, usage load: in this case, dimensioning is used for planning in an existing network.
Network dimensioning is particularly important because it can be used to simultaneously ensure consistent customer experience, while also minimising capital and operational expenditure. Dimensioning can be carried out for both the short term (responding to traffic growth and local fluctuations) and the long term (planning and costing forward-looking traffic/product/service forecasts).
Currently, analysis of certain networks—those where network resources are shared in non-fixed amounts between users—provides insufficient information for accurate load analysis, network dimensioning, and network planning. An example of such a network is one using the Universal Mobile Telecommunications System (UMTS), a ‘Third Generation’ (3G) standard based on a Wideband Code Division Multiple Access (WCDMA) standard.
Dimensioning 3G networks is enormously more complex than dimensioning 2G networks, which is a relatively trivial task. As a WCDMA system, the 3G radio access network (RAN) has “soft” capacity limits. That is, each cell of the RAN serves different radio environments, traffic profiles and user behaviours, all leading to different and variable capacity limits. Accordingly, the amount of traffic that a cell can carry without adversely affecting customer experience can vary dramatically from cell to cell. Additionally, transport network (TN, the interconnections between base transceiver stations and radio network controllers) connection admission control and congestion management processes offer considerable control at the cost of greater complexity.
Currently, there are very few network dimensioning tools available commercially. Those that do exist appear to be added as an after-thought to network planning tools, and are based on simplistic assumptions that tend to be inappropriate for a WCDMA environment. For example, existing dimensioning tools are primarily oriented towards radio frequency (RF) and cell planning, with traffic and capacity modelling being implemented only to the extent required to support cell planning.
Dimensioning modules built into RF and cell planning tools tend to focus exclusively on management of uplink, and sometimes downlink and noise rise, instead of a broader analysis of radio resource management procedures.
Overly simplistic tools and processes for dimensioning can lead to excessive capital expenditure due to a necessarily conservative approach, or to a poor customer experience as a result of insufficient hardware provisioning.
It is desired to provide a system and process for dimensioning a cellular telecommunications network that alleviate one or more of the above difficulties, or at least that provide a useful alternative.